The centralized development of procedures to efficiently transduce CD34+ hematopoietic stem cells from patients with Thalassemia will permit standardization of procedures, facilitate the exchange of information and expertise between the 2 clinical trial sites (MSKCC & Thessaloniki), and be cost effective. Core Unit B will mainly focus on the optimization of clinical processes and on their implementation throughout the clinical trial. The staff of MSKCC will train the staff from Thessaloniki in CD34+ cell transduction procedures and will oversee the implementation of CD34+ cell transduction and biosafety testing at both clinical sites. The specific aims of Core Unit B are to perform and/or coordinate 1) the validation of B-globin vector transduction conditions for G-CSF- and G-CSF/AMD3100-mobilized CD34+ cells from patients; 2) the transduction of patient cells at MSKCC and in Thessaloniki and ensure, via training and QA oversight, that similar transduction procedures are implemented at both clinical sites. This process entails the short-term culture and transduction of CD34+ patient cells from mobilized patients with B-globin vector stocks in semi-closed systems in collaboration with the investigators of each clinical trial; 3) the biosafety release testing of transduced patient CD34+ cells for both clinical sites. This includes the testing for replication-competent lentivirus and other biosafety testing in end-of-production transduced CD34+ cells; 4) the collection and analysis of PBMCs and bone marrow (BM) samples at regular intervals post-infusion to ensure the molecular and biosafety monitoring of patients treated at both clinical sites. Hence, Core Unit B will determine the vector copy number in patient blood and BM samples. It will also coordinate and distribute study materials and resulting data for the vector integration site studies; 5) the banking and storage of U-globin clinical vector stocks and the freezing and cell banking of IS-globin transduced CD34+ cells and clinical specimens. In addition. Core Unit B will provide expert advice and protocols for lentiviral vector production and cell transduction to other projects. It will also supply B- globin vector stocks and clinical patient samples for functional studies involving vectors' new insulators.